Dental floss is used to clean the interproximal spaces between adjacent teeth and for massaging the gums at the interproximal. Many dental floss applicators have been commercially marketed as a sanitary substitute for otherwise using one's fingers to hold a short length of floss between two hands. Dental floss is composed of a twisted multi-strand material composite which readily frays during use and is easily broken unless carefully applied. The dental applicators currently on the market do not permit dental floss to be controllably unwound from a supply roll in such a way that a short, pre-selected length of dental floss may be dispensed and locked to hold a pre-selected length under tension during flossing. In addition, dental floss applicators currently marketed are not adaptable for use with orthodontic braces and have minimal utility for flossing fixed permanent bridges in situ within the mouth.